Re: [PATCH v4 27/39] arm64: kasan: Enable in-kernel MTE

[Catalin Marinas]

On Fri, Oct 02, 2020 at 01:10:28AM +0200, Andrey Konovalov wrote:
> diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
> index 23c326a06b2d..6c1a6621d769 100644
> --- a/arch/arm64/mm/proc.S
> +++ b/arch/arm64/mm/proc.S
> @@ -40,9 +40,15 @@
>  #define TCR_CACHE_FLAGS	TCR_IRGN_WBWA | TCR_ORGN_WBWA
>  
>  #ifdef CONFIG_KASAN_SW_TAGS
> -#define TCR_KASAN_FLAGS TCR_TBI1
> +#define TCR_KASAN_SW_FLAGS TCR_TBI1
>  #else
> -#define TCR_KASAN_FLAGS 0
> +#define TCR_KASAN_SW_FLAGS 0
> +#endif
> +
> +#ifdef CONFIG_KASAN_HW_TAGS
> +#define TCR_KASAN_HW_FLAGS SYS_TCR_EL1_TCMA1
> +#else
> +#define TCR_KASAN_HW_FLAGS 0
>  #endif
>  
>  /*
> @@ -427,6 +433,10 @@ SYM_FUNC_START(__cpu_setup)
>  	 */
>  	mov_q	x5, MAIR_EL1_SET
>  #ifdef CONFIG_ARM64_MTE
> +	mte_tcr	.req	x20
> +
> +	mov	mte_tcr, #0
> +
>  	/*
>  	 * Update MAIR_EL1, GCR_EL1 and TFSR*_EL1 if MTE is supported
>  	 * (ID_AA64PFR1_EL1[11:8] > 1).
> @@ -447,6 +457,9 @@ SYM_FUNC_START(__cpu_setup)
>  	/* clear any pending tag check faults in TFSR*_EL1 */
>  	msr_s	SYS_TFSR_EL1, xzr
>  	msr_s	SYS_TFSRE0_EL1, xzr
> +
> +	/* set the TCR_EL1 bits */
> +	mov_q	mte_tcr, TCR_KASAN_HW_FLAGS
>  1:
>  #endif
>  	msr	mair_el1, x5
> @@ -456,7 +469,11 @@ SYM_FUNC_START(__cpu_setup)
>  	 */
>  	mov_q	x10, TCR_TxSZ(VA_BITS) | TCR_CACHE_FLAGS | TCR_SMP_FLAGS | \
>  			TCR_TG_FLAGS | TCR_KASLR_FLAGS | TCR_ASID16 | \
> -			TCR_TBI0 | TCR_A1 | TCR_KASAN_FLAGS
> +			TCR_TBI0 | TCR_A1 | TCR_KASAN_SW_FLAGS
> +#ifdef CONFIG_ARM64_MTE
> +	orr	x10, x10, mte_tcr
> +	.unreq	mte_tcr
> +#endif

Don't we miss the TBI1 bit here? I think the v3 version of this patch
was better.

-- 
Catalin